about 0.96 exhaust housings . too big for 7M?

[supramaze]

didnt find any clear answers from searching, so here goes

I have just mounted a new turbo, T4 , with 67mm compressor 0.70 AR and 70mm turbine 0.96 AR, Journal bearings, and everything looks quite cool with this turbo, BUT

cant get it to spool, have no boost at all under 4300 rpm. boost starts to climb very slowly and reaches 14psi at 6500 rpm, which is no use for me. have plenty of supports and built engine for atleast 600 hp, heck even a standalone EMS. no boost leaks (pressure tested pipes, manifold, OK), checked the 50mm external wastegate for proper funktion, its ok. last summer with a another turbo (61mm, ballbearings) , i boosted 22psi easy with no problems, and boost begun at 3800 rpm with that one.

its seems like this new 67mm turbo doesnt spinn like it should, maybe the bearings are fubar? its a brand new turbo and yes i did prime it before startup

anyone with experiences with 0.96 AR on a 7MGTE ?

 

[suprahero]

Send this guy a pm. He'll know if no one answers.
http://www.supramania.com/forums/member.php?find=lastposter&t=48898
http://www.supramania.com/forums/member.php?u=221

 

[MDCmotorsports]

Shouldn't be too large. I was running a Q trim garrett turbine with a .98 rear housing on my 7m, and I had full 10psi @ 4000 rpms.

Check to make sure your wastegate is working and is seated (not leaking).

I had the turbo do the same thing you just described. I could at most, make 4psi @ 6,000rpms. I then found out that the wastegate vavle was not seated.

 

[becauseican]

A T4 .96 a/r is way too big for a 7m on the street. Most guys use a .68, .70 a/r, and even with these they will make full boost at 4000-4500 rpms. I use a .58 a/r on my 1jz with a T61 and I love it, it makes full boost at 3700-3800 rpm, but the power does drop off a little in the top end.

 

[suprahero]

Sorry Jon, I forgot you were a turbo guru as well. I looked at the main page and they had Doward listed.

 

[logan]

Is your turbo a ebay china super cheepie turbo ?

 

[supramaze]

thanks everyone for your replies, keep em coming. yeah I have checked the wastegate , its naturally suspected when boost doesnt appear as it should. the manifold is pressure tested, the flanges are straight and gaskets all in place. the valve seat pushes nice against valve, so I believe it should be ok. the wastegate has a 11 psi spring in it, and the wastegate is controlled by my EMS using dual port boost control. so pressure is applied to top port , to help the gate to keep closed.

one thing that I dont like about it, its almost not spinning at all with engine idling at 1000 rpms. cannot be normal, can it ? the smaller ballbearings turbo i had, had at lot more spinning at idle, and took almost 30 sec to stop after shutdown.

thanks for all help i can get

 

[supramaze]

Is your turbo a ebay china super cheepie turbo ?

hm it should not be one of those. in fact its a "OBX racing" T4 turbo, manufactured,assembled and balanced in USA. so its says anyways. price tag about 550 USD

but, maybe i got ripped off damn feels like so


my other smaller 61mm turbo was a Turbonetics

 

[MDCmotorsports]

Sounds like the turbo is not put together well. Pics of your turbo please.

 

[supramaze]

heres a link, specs and info can be found there
http://cgi.ebay.com/ebaymotors/ws/e...&viewitem=&item=170099678308#ebayphotohosting

 

[MDCmotorsports]

Thats just a p trim with a .98 rear housing. That should take off before 4k rpms.

Some thing is wrong with the wastegate, turbo, or you have a huge pre-turbo exhaust leak.

Also, check your cam timing and ignition timing.

 

[tte]

Always best to get your turbo checked out when buying from ebay.

Cheers,
Roy

 

[MRSUPRA]

We keep warning people about Egay turbos. Oh well..

BTW, a .96 A/R turbine housing is too big on a turbo that size unless you plan on making 800+rwhp or reving your engine like a honda motorcycle. A .68 will give you much better spool and still be capable of over 700rwhp.

 

[rakkasan]

A T4 .96 a/r is way too big for a 7m on the street. Most guys use a .68, .70 a/r, and even with these they will make full boost at 4000-4500 rpms. I use a .58 a/r on my 1jz with a T61 and I love it, it makes full boost at 3700-3800 rpm, but the power does drop off a little in the top end.

What he said. I run a .58 also on my 1jz & love it. Smaller displacement motor, sure, but it shouldn't make that much of a difference.....

 

[dbsupra90]

what kind of wastegate do you have?

 

[supramaze]

what kind of wastegate do you have?

its a HKS 50 mm clone, that has been taken apart and looked over, pressure tested, shaft was polished and put together again. exhaust manfold has been pressure tested too. valve-seat sits between wastegate flange och the wastegate.

about journal bearings, when your engine idles at 1000 rpms, does it spinn at pretty high speed and how long does it take to stop?

 

[LordLo]

My ebay hks wastegate clone is shitty. When it's cold, it works fantastic, sometimes I hit 12 psi. When its warmed up from spirited boosting, I can only get 5 psi at best. haha. I still got to take it apart one of these days and see what's up with the spring. :3d_frown:

I get full boost at around 4,000-4,500 rpms, but i have a .84 housing.

 

[dbsupra90]

its a HKS 50 mm clone, that has been taken apart and looked over, pressure tested, shaft was polished and put together again. exhaust manfold has been pressure tested too. valve-seat sits between wastegate flange och the wastegate.

about journal bearings, when your engine idles at 1000 rpms, does it spinn at pretty high speed and how long does it take to stop?

do you have the flange w/ the lip? (the one at the bottom above the bolts)

ive seen a few of the clones come without that piece. that has to be installed and w/ the lip facing the wastegate. just making sure.

 

[VanSupra]

We keep warning people about Egay turbos. Oh well..

BTW, a .96 A/R turbine housing is too big on a turbo that size unless you plan on making 800+rwhp or reving your engine like a honda motorcycle. A .68 will give you much better spool and still be capable of over 700rwhp.

I agree with this as I am running a Turbonetics T70 Q Trim with the .68 hot side but the spool isn't that great but better than the .81 I exchanged out. Even with a .96 your turbo should be spinning freely even if it's a non ball bearing journal type. Send it back. I do have a fresh IHIRC7 turbo with an 18cm rear housing possibly for sale. hth

 

[supramaze]

do you have the flange w/ the lip? (the one at the bottom above the bolts)

ive seen a few of the clones come without that piece. that has to be installed and w/ the lip facing the wastegate. just making sure.[/QUOTE]


yeah I have that piece installed aswell. its the valveseat with the lip facing wastegate valve. if I look a the valve, its clear that it pushes against it, it has markings on it


I even tried a desperate thing, I pressurized the top port with 30 psi of constant air pressure, expecting the boost to go wild . so with full attention on boost, I got out and test it. and , noooooo still no more boost than slowly building to 12-14 psi at 6500 rpms... that with the gate forced closed. so, that leaves me with not suspecting the wastegate anymore

something must be wrong with bearings or turbine. POS